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www.thinkSRS.com Pharmacopeia vs. Thermodynamic Melting Point Determinations Application Note #3 Pharmacopoeia Melting Point The procedural rules for melting point determinations are defined in the pharmacopeias. The medical handbooks include minimum requirements for the design of the melting point apparatus and for performing the measurements. Automated melting point determination procedures are generally included. Very often, the pharmacopeias also list special methods for difficult or unusual cases of melting point determination. Figure 1. Standard capillary tubes used in melting point determinations. The pharmacopeias regard the capillary technique as the standard method for melting point determination. In this method, thin glass capillary tubes containing packed samples of the substance are introduced into a heating stand that is continuously being heated up. The capillary technique is the standard method used for melting point determinations in most organic and pharmaceutical chemistry laboratories. The procedures for melting point determinations in the pharmacopeias call for a fixed rate of temperature rise in the "heating stand" (i.e. liquid bath and/or metal block), typically between 0.2